wierd screeching noise from the intake manifold

facime · Post by **facime** » 04 Mar 2017, 19:43

When I bought this car (very cheaply, I might add) It had a very erratic idle. It would idle hunt and idle low and roughly. I pulled the ETM out and cleaned the build up from inside the throttle body. It was an immediate improvement. The engine idles smooth and no hunting anymore.

HOWEVER...now it has this bizarre noise that has be stumped. Its a hollow howling whistle and using a stethoscope Ive isolated the noise to definitely be originating from the intake somewhere. The other odd thing is that this noise goes away once the car starts to build any temperature at all.

It goes like this:
Start the car and no noise. About 10-15 seconds after starting the car the noise comes on slowly, then gets louder (to the point you will hear in the video). If I rev up the engine at this point the noise does change pitch but does NOT go away. After about a minute or so of idling the noise fades away and is completely gone until the car is completely cold again.

Ive ruled out driven accessories by pulling the drive belt and testing. noise still present.

Here is a video of the noise.
(ignore the smoking at the back of the motor, I spilled some ATF while flushing the power steering)

https://youtu.be/1YvtzENxC4U

Has anyone ever heard anything like this before?

Post by **June** » 04 Mar 2017, 22:58

Sounds like a bearing on a pulley or water pump or even the alternator. You could remove the serpentine belt to eliminate all the accessories. I have heard sounds like that when water pumps have gone bad before, just never had a Volvo have one go bad yet.

facime · Post by **facime** » 04 Mar 2017, 23:19

as stated in the original post:

Ive ruled out driven accessories by pulling the drive belt and testing. noise still present.

I agree however that it sounds like a bearing, and the fact that its there only when cold seems to support that, but I'll be damned if I can figure out what bearing.

Post by **abscate** » 06 Mar 2017, 10:21

If it doesn't go after serpentine belt removal, remove the upper timing belt cover and listen at the VVT - and get on this quick - it is about to blow..

A cam seizure will take out the top end of your engine.

Legofan · Post by **Legofan** » 07 Mar 2017, 18:21

That sounds like it might be the oil trap. Remove the oil cap when you start it and see it the noise stops.

Here is the same noise on an S40

ThommyKent · Post by **ThommyKent** » 09 Mar 2017, 00:43

It`s not the VVT don`t worry about that.

facime · Post by **facime** » 09 Mar 2017, 22:11

Legofan wrote:That sounds like it might be the oil trap. Remove the oil cap when you start it and see it the noise stops.

Here is the same noise on an S40

BINGO! we have a winner. I guess I'll have to do a little research into how to fix this problem. What's the typical repair for this problem?

ThommyKent · Post by **ThommyKent** » 09 Mar 2017, 22:20

Clean out the PCV system.
This is for an 850, but is basically the same repair. Have fun!

facime · Post by **facime** » 10 Mar 2017, 14:46

Thanks, looks like a bit of a pain in the ass, but Ive worked hard to get this car back up to snuff, so looks like I'll order a kit and get busy next week.
I had suspected that it was something to do with all those hoses under there, but its good to have some confirmation and a plan of attack. This car only 108K miles on it, but the PO obviously just let stuff go. Also it looks like this service is part of the 105K mile schedule so I guess its right on cue.

Legofan · Post by **Legofan** » 10 Mar 2017, 14:58

facime wrote:Thanks, looks like a bit of a pain in the ass, but Ive worked hard to get this car back up to snuff, so looks like I'll order a kit and get busy next week.
I had suspected that it was something to do with all those hoses under there, but its good to have some confirmation and a plan of attack. This car only 108K miles on it, but the PO obviously just let stuff go. Also it looks like this service is part of the 105K mile schedule so I guess its right on cue.

From one T6 owner to another, have the timing belt replaced, it's time. Secondly, get your oil changed on time at 3k intervals. The VVT relies on good clean oil pressure as well as the timing advance solenoid.

A few things I can recommend that will help bring it back to new:

Rear shocks and upper mounts, FCPEURO has a Meyle kit that's affordable.
Replace all four sway bar links, I got mine off Rockauto. Europarts brand is good.
Replace the inner and outer tie rods. Rockauto for these as well.
IPD has a great upper engine mount upgrade, I highly recommend it.
Check your engine cross member, if you can move it back and forth then replace the mounts.
Lastly, get some subframe inserts, IPD has a kit and its cheap.

Oh and check your control arm bushings.

Good luck and welcome to the club.